Effect of Plant Spacing and Nitrogen Levels on Growth, Herb and Oil Yields of Lemongrass (Cymbopogon flexuosus (Steud.) Wats. var. I cauvery)

A field experiment was conducted for 2 years during 1991–93 at the Central Institute of Medicinal and Aromatic plants, Bangalore, India to study the effect of plant spacings (60 × 60, 60 × 45, 60 × 30 and 45 × 45 cm) and nitrogen levels (0, 50, 100 and 150 kg N ha⁻¹ year⁻¹) on growth, herb and oil yield of lemongrass. A closer plant spacing of 45 × 45 cm resulted in higher herb and oil yields compared to wider spacing of 60 × 60 cm. Application of 150 kg N ha⁻¹ year⁻¹ resulted in higher herb and oil yields. Higher nitrogen applications also increased the plant height and number of tillers per clump. The oil content and quality-was not influenced by spacing and nitrogen levels.     

Optimum Seed Rate and Nitrogen Fertilizer Requirement of Rice Under Semi-deepwater Ecosystem

The effect of varying seed rates (100–1000 seeds m⁻²) and nitrogen fertilizer (0–60 kg N ha_-1) applied either in a single basal dose or in splits was investigated on a tall elongating, photosensitive rice variety, Nalini, under semi-deepwater conditions (0–100cm) during 1993 and 1994 at Cuttack, India. Seedling emergence was higher in 1993 (53.9 %) than in 1994 (44.1 %) and it increased proportionately with increasing seed rate, Increase in the number of tillers and panicles m⁻² at higher seed rates was associated with a corresponding decrease in panicle weight. Regression analysis indicated a decrease of 0.91–1.28g in panicle weight for an increase of 100 panicles m⁻². The grain yield of rice was significantly higher at 400 seeds m⁻² in 1993 and at 600 seeds m⁻² in 1994 than at low seed rates but further increase in seed rate did not increase the yield. Application of N fertilizer increased the panicle number and thereby grain yield significantly. The effect of basal and split applied N at active or maximum tillering stages as well as between 30 and 60 kg N ha⁻¹ was not significant on the grain yield. The results suggest that a basal dose of 30kg N ha⁻¹ and seeding density of 400–600 seeds m⁻², resulting in 40–50 % seedling emergence and 150–200 panicles m⁻², each with 2.0–2.5 g weight, may be adequate for optimum productivity of rice under semideepwater conditions.     

Effect of High Lucerne (Medicago sativa L.) Sowing Rates on Establishment Year Yield, Stand Persistence and Forage Quality

The effect of very high sowing rates on establishment year dry matter (DM) yield and stand persistence of irrigated lucerne ( Medicago sativa L.) was studied. Two cultivars ('Peace' and 'Apollo II') were sown in 1986 at two row spacings and six sowing rates from 5.6 to 50.4 kg ha⁻¹. Established seedling density (S_d) increased linearly with sowing rate (R):S_d= 24.1R. Establishment year DM yield increased at sowing rates from 5.6 to 16.8 kg ha⁻¹, levelled off as sowing rate increased to 33.6 ka ha⁻¹, and then decreased as sowing rate increased further. Thus, there was a broad optimum sowing rate that gave a maximum sowing year DM yield. Percent plant survival to the third year (1988) decreased with increasing sowing rate so that plant densities became similar for sowing rates greater than 16.8 kg ha⁻¹. Within the range 5.6 to 16.8 kg ha⁻¹, increasing sowing rate increased stand persistence measured as 1988 plant density; however, a corresponding increase in DM yield was not obtained. For all full-production years, DM yield was independent of sowing rate. Sowing rate did not affect three chemical measures of forage quality.     

Einfluß der Bestandesdichte auf Ertrag und Qualität der Zuckerrübe bei unterschiedlichem Erntetermin

The effect of plant population on yield and quality of sugar beet at different harvesting date
Optimum plant population of sugar beet in respect of corrected sugar yield in Central Europe ranges from 70 000 to 90 000 plants/ha. It is known that extending the length of growing period by later harvesting causes an increase in yield and quality of sugar beet depending on location and weather. There is a lack of information, however, about the effect of plant population on yield and quality increase with postponed harvesting date.
The objective of this study was to investigate the influence of plant density and harvesting date on yield and quality of sugar beet.
Four trials were carried out at Göttingen (Lower Saxony) from 1982 to 1985 which included each year four plant populations and three harvesting dates (end of September to middle of November).
Depending on seed lot, plant spacing and field emergence, plant populations varied between 87 000 and 27 000 plants/ha. Averaged over the years, the plant populations for the different treatments reached 71 000, 51 000, 40 000 and 31 000 plants/ha.
Later harvesting date and increasing plant population resulted in higher yield of beet and/or higher sugar content of beet. The increase in corrected sugar yield with extending the length of growing period was highest in plant populations with high density.
From the results it can be concluded that by having the choice, a beet crop with the highest plant population should be harvested at the end, a crop with a lower plant population at the beginning of the harvesting period, unless there have to be observed some other aspects (location, crop sequence, field condition).     

Analysis of Growth and Productivity of Indian Mustard (Brassica juncea) in Relation to FYM, Nitrogen and Source of Fertilizer

A field experiment was conducted during the winter seasons of 1992–93 and 1993–94 at Anand to study the effect of FYM, nitrogen and source of fertilizer on growth and yield of mustard [ Brassica juncea (L.) Czernj & Cosson]. The results showed significant variation in leaf area index (LAI), crop growth rate (CGR), dry matter production and seed yield. The direct effect of farmyard manure (FYM) was conspicuous in improving the growth of mustard. FYM application at 10 tonnes ha⁻¹ significantly increased the LAI, CGR and dry matter accumulation per plant at almost all the stages during first year study (1992–93) and in pooled analysis. Similarly, nitrogen application registered maximum LAI, CGR at 75 kg level and RGR and NAR at 50 kg level at almost all the during both years. Sulphur carrying source (Ammonium sulphate plus single super phosphate) increased all stages growth characters. Maximum dry matter accumulation per plant and seed yield were recorded with highest levels of FYM (20 tonnes ha⁻¹), N (75 kg ha⁻¹) and source having S. Seed yield was strongly associated with LAI and dry matter accumulation per plant at all the stages.     

Effect of Gibberellic Acid Spray and Basal Nitrogen and Phosphorus on Productivity and Fatty Acid Composition of Rapeseed-Mustard

Two field experiments were conducted during] 994-95 to study the effect of spray of 10⁻⁵ M GA3 at 40 days after sowing on mustard ( Brassica juncea (L.) Czern & Coss.) cv. Varuna grown with basally applied 0, 40, 80 and 120 kg N ha⁻¹ (Expt. 1) and 0,15, 30 and 45 kg P ha⁻¹ (Expt. 2) on pod number per plant, seeds per pod, 1000 seed weight, seed yield, biological yield, harvest index and fatty acid composition of oil. No significant difference between water and GA3 spray was found when basally applied nitrogen was 0 or 40 kg N ha⁻¹. N₈₀ proved to be the best for yield characteristics. In another experiment on phosphorus, GA₃ and 30 kg P ha⁻¹ individually enhanced the yield, but interaction of GA₃ and P remained non-significant. The fatty acid composition of oil in both experiments was significantly affected only by nitrogen and phosphorus treatments for oleic acid and erucic acid. It was found that return in the form of yield was more for every kg applied fertilizer under GA, spray treatment. The response was more for N fertilizer in comparison to P. GA₃ at a low level of fertilization significantly increased the return from fertilization.     

Die Wurzelentwicklung von Zuckerrübenpflanzen auf einem Sandlöß-Standort und ihre Bedeutung für die Stickstoffernährung

Root development of sugar beet plants on a sandy loess site with regard to nitrogen nutrition.
Root development of sugar beet plants in a sandy loess soil (Haplic Phaeozem) was observed from the early seedling stage up to harvest by measuring at first the greatest vertical and lateral extension of the root systems of single plants and later the rooting density of the whole plant stands (auger method, profile wall method).
During the seedling stage not only the subsoil, but also large parts of the topsoil between the plants remained unoccupied by the root systems. In this phase the greatest lateral extension of single roots reaches nearly the length of the greatest leaf of the plant. With the closure of the canopy the rooting density in the topsoil accounts to 1–2 cm cm⁻³.
In summer roots penetrate to a depth of 100–150 cm with rooting densities of 0.1 to 1 cm - cm⁻³. Thus, the plants gain not only access to water reserves, but sometimes meet remarkable amounts of nitrate which under the relatively dry conditions of the region tends to accumulate in 60–120 cm depth and – when taken up by the beet plants in the late stage of growth – affects crop quality negatively.     

Interactive Effect of Nitrogen and Sulphur on Growth and Yield of Rape-seed-Mustard (Brassica juncea L. Czern. and Coss. and Brassica campestris L.) Genotypes

A simple randomized field experiment was conducted to assess the growth and yield of rape-seed-mustard in relation to sulphur and nitrogen interaction. Three levels of sulphur (0, 40 and 60 kg ha⁻¹) in combination with three levels of nitrogen (60, 100 and 150 kg ha⁻¹) were tested as treatments, T₁, T₂, T₃, T₄, and T₅. Results indicated significant favourable effects of sulphur and nitrogen, when applied together, on yield components, seed and oil yield. Maximum response was observed with treatment T₃ (having S and N of 40 and 100 kg ha¹, respectively). Percentage oil content of seed was maximal at T₄ (having S and N of 60 and 100 kg ha¹) in both cultivars. The increase in N dose from 100 to 150 kg ha⁻¹ without any change in applied S, i.e. 60 kg ha¹ (T₅), decreased the percentage oil content. The seed and oil yield, however, were similar to T₃. Favourable responses of S and N interaction on leaf area index, rate of photosynthesis and biomass production were also observed.     

Effects of Sugar Beet as a Preceding Crop on Cotton

Cotton ( Gossypium hirsutum L.) is one of the most profitable cash crops in Greece. It is usually grown as a monoculture but it is also found in rotation systems with other plant species including sugar beet ( Beta vulgaris L.). Poor cotton performance following sugar beet was persistently reported by farmers. Glasshouse and field experiments were conducted to determine whether: 1) sugar beet as a preceding crop affected seed germination, seedling growth and yield of cotton; and 2) N fertilization can minimize the effects of sugar beet. Seedling growth was diminished by sugar beet extracts; emergence, seed-cotton, stalks and biomass of cotton in pots were affected by the soil incorporation of sugar beet residues; and emergence, flowers, bolls and seed-cotton production in the field were also affected by the soil incorporation of sugar beet residues. These harmful effects were eliminated by N fertilization.     

Effect of Integrated Use of Farmyard Manure and Sulphur in a Soybean and Wheat Cropping System on Nodulation, Dry Matter Production and Chlorophyll Content of Soybean on Swell-Shrink Soils in Central India

In a 3-year experiment on a Typic Haplustert low in soil test sulphur (S), the response to applied farmyard manure (FYM) and S was studied in terms of the nodule production, nodule dry weight, chlorophyll content, dry matter production and seed yield of soybean. FYM was applied to soybean at four levels (0–16 t ha⁻¹). S as gypsum was also applied at four levels (0–60 kg ha⁻¹) to both soybean and wheat every year. Both total and active nodule production, nodule dry weight, dry matter production and seed yield of soybean were increased significantly by the application of both FYM and S. However, the proportion of total nodules to active nodules fell sharply for applications higher than 8 t FYM and 40 kg S ha⁻¹.     

Response of Mustard (Brassica juncea L.) to Applied Nitrogen with or without Ethrel Spray under Non-irrigated Conditions

Field studies were conducted during the winter seasons of 1995–96 and 1996–97 at the Agricultural Farm of Aligarh Muslim University, Aligarh, India on mustard ( Brassica juncea L. Czern & Coss., var. Alankar) under non-irrigated conditions, to evaluate the effect of foliar spray of 200 p.p.m. ethrel (2-chloroethyl phosphonic acid) at flowering growth stage along with basal 0, 40, 80 or 120 kg N ha⁻¹ on net photosynthetic rate (P_N), stomatal conductance (C_S), stomatal resistance (R_S), leaf K content, relative water content (RWC), leaf area index (LAI) and total dry matter (TDM) production monitored at 20 days after spray application, and plant N content, seed N content, nitrogen harvest index (NHI), nitrogen yield merit (NYM), pods plant⁻¹, 1000 seed weight, seed yield, biological yield, harvest index (HI), seed yield merit (SYM) and merit of genotype (MOG) at harvest. Results indicated that, at 0 or 40 kg N ha⁻¹, ethrel did not produce any significance effect, but at basal 80 kg N ha⁻¹, ethrel affected the parameters favourably with the exception of 1000 seed weight, HI, seed N and NHI. Ethrel-sprayed plants utilized N from the soil more effectively and showed increased NYM. Yield attributes, seed yield and merit of genotype (in terms of NYM and SYM) were also enhanced. Ethrel spray enhanced seed yield under water stress conditions mainly by increasing K uptake and retaining higher RWC, thereby decreasing R_S and increasing LAI, P_N and TDM production.     

The Effect of Nitrogen and Phosphorus Fertilization on the Phosphorus Absorption by Sunflowers

Little is known about the effect of fertilization on the P uptake of sunflowers. A 4² factorial trial with 0, 60, 120 and 180 kg N ha⁻¹ and 0, 15, 30, and 45 kg P ha⁻¹ was conducted over three years. The P content and concentration of leaves, stems and capitula were determined at three growth stages. High N levels increased the P content and concentration of all plant components in early growth stages only. High P levels increased the P content and concentration of all plant components sharply almost throughout. Plants seem to recover some lost growth towards the end of the season so that at physiological maturity there are no significant differences in P content among N levels. The translocation of P from the stems is very effective but P can accumulate in the leaves if a luxury quantity of P is present in the plants. In terms of seed yield a significant N × P interaction was found, indicating a sharp response to both N and P only in the presence of a sufficient quantity of the other element. The response of seed yield was in agreement with the P absorption by the plants.     

Estimation and Partitioning of Nitrogen Fixed by Soybean in Mediterranean Climates

A field study was conducted to estimate the nitrogen fixation by soybean [ Glycine max (L.) Merr.], using the A-value and the N-difference methods, and to examine the N partitioning within the plant. The cultivar Clark and its non-nodulating isoline (as reference crop) were grown in a silty clay (Typic Xerothent) soil, in 1991 and 1992. ₁₅N-Labelled fertilizer was surface applied in solution, at rates of 20 and 100 kg N ha⁻¹ to the nodulating and non-nodulating soybean, respectively. Plant samples were taken at full bloom (R2), beginning of seed growth (R5) and physiological maturity (R7). There was little nitrogen fixation at the early growth stages but it increased rapidly during the seed filling period. At R7 nitrogen fixed was estimated by the A-value method as 155 kg N ha_-1 in 1991 and as 240 kg N ha⁻¹ in 1992. The corresponding estimates by the N-difference method were significantly smaller. The seeds had a higher, and the vegetative parts smaller, proportion of fixed nitrogen compared to the whole plant. During the seed filling period, the translocation efficiency for fixed nitrogen was greater (93 % in 1991 and 85 % in 1992) compared to the N derived from soil (75 and 56 %, respectively). It was estimated that, after the harvest of pods, the soil was depleted by a net amount of 121 kg N ha⁻¹ in 1991 and 90 kg N ha⁻¹ in 1992.     

Drying and Storage Method to Prolong Seed Viability and Seedling Vigour of Rabi-summer-produced Groundnut

Rabi-summer-produced (dry season, February–May) groundnut ( Arachis hypogaea L.) cv. GG 2 was dried using three different methods, viz. windrow (W), windrow-shade (WS) and DOR (Directorate of Oilseeds Research) methods and stored in polyethylene lined gunny bags with or without desiccant (CaCl₂ or silica gel, 10gkg⁻¹ pods). The seeds were analysed for the retentation of seed viability, seedling vigour, membrane integrity and Held emergence during storage, and crop stand and pod yield after 12 months of storage. The drying and storage method significantly affected the getminability, seedling vigour and field emergence. Both root length and seedling biomass were adversely affected due to windrow drying (W) The quick loss of viability in the W treatment was associated with an increase in electrical conductivity of the seed leachate. The retention of higher seed viabiliry and vigour in the seeds dried by DOR method and stored with CaCl₂ (DOR C) was due to lower drying remperarures and lower pod moisture during the initial storage period. The DOR C method was found to be an effective drying and storage method for retaining acceptable seed viability and vigour till the following rabi-summer sowing of groundnut.     

Response of Mustard to Ethrel Spray and Basal and Foliar Application of Nitrogen

In a field trial conducted during 1992–93 and 1993–94, the effect of basal (B) nitrogen (N) (45 and 60 kg N ha⁻¹) and foliar application (F) of water (W) or 10 kg N ha⁻¹ and 400 or 600 ppm ethrel (E) (2-Chloro ethyl phosphonic acid) at 70 days after sowing was studied on leaf area index and dry mass at 90 days and pod number per plant, seeds per pod, 1000 seed weight, seed yield, oil content and oil vield at harvest of mustard ( Brassica juncea L. Czern & Coss.) cv. T-59. Recommended basal (B) application of 90 kg N ha (BN₉₀) was used as control. On the basis of 2 year data it was found that basal application of 60 kg N and foliar spray of 10 kg N ha ⁻¹ and 600 ppm ethrel gave higher values for growth and yield characteristics and enhanced seed yield and oil yield by 12.5 and 14.8%, respectively over control BN_90.     

The Effect of Nitrogen Fertilization and Population Density of the Field Bean (Vicia faba L. minor) of Indeterminate and Determinate Growth Habit on the Symbiosis with Root Nodule Bacteria and on the Seed Yield

Field beans of indeterminate (cv. Nadwiślański) and determinate (cv. Tibo) growth habits were grown on field plots with a density of 20, 40 and 80 plants m⁻² at two levels of nitrogen fertilization: low (20 kg N ha⁻¹) and very high (150 kg N ha⁻¹). At the phase of intense pod growth the number and the dry matter weight of root nodules as well as their nitrogenase activity and some features of the plants growth were determined, and in the period of ripeness the components of seed yield were established.
It was found that increased density of sowing as well as the high level of nitrogen fertilization inhibited the growth and development of root nodules and limited their nitrogenase activity in both cultivars. Plants of both varieties were characterized by a similar potential of forming the root nodules, however, in plants of the cv. Tibo the nitrogenase activity of nodules was much lower than in the cv. Nadwiślański.
Increased population density of the plants has in both varieties given increased seed yield when calculated per m² of the soil, compensating in excess the depression of the seed yield from one plant. Such compensation did not occur in the case of the depression of nitrogen fixation under intense nitrogen fertilization.     

Studies on Sowing Depth for Chickpea (Cicer arietinum L.), Faba Bean(Vicia faba L.) and Lentil (Lens culinaris Medik) in a Mediterranean-type Environment of South-western Australia

Pulses such as chickpea, faba bean and lentil have hypogeal emergence and their cotyledons remain where the seed is sown, while only the shoot emerges from the soil surface. The effect of three sowing depths (2.5, 5 and 10 cm) on the growth and yield of these pulses was studied at three locations across three seasons in the cropping regions of south-western Australia, with a Mediterranean-type environment. There was no effect of sowing depth on crop phenology, nodulation or dry matter production for any species. Mean seed yields across sites ranged from 810 to 2073 kg ha⁻¹ for chickpea, 817–3381 kg ha⁻¹ for faba bean, and 1173–2024 kg ha⁻¹ for lentil. In general, deep sowing did not reduce seed yields, and in some instances, seed yield was greater at the deeper sowings for chickpea and faba bean. We conclude that the optimum sowing depth for chickpea and faba bean is 5–8 cm, and for lentil 4–6 cm. Sowing at depth may also improve crop establishment where moisture from summer and autumn rainfall is stored in the subsoil below 5 cm, by reducing damage from herbicides applied immediately before or after sowing, and by improving the survival of Rhizobium inoculated on the seed due to more favourable soil conditions at depth.     

Effect of Sodium Chloride Salinity on Seedling Emergence in Chickpea

Although laboratory (Petri dish) germination as an estimate of seed viability is a standard practice, it may not give an accurate prediction of seedling emergence in the field, especially when saline irrigation water is used. Experiments were conducted to investigate seedling emergence in two chickpea cultivars (ILC 482 and Barka local) in response to varied salinity levels and sowing depths. Seeds were sown in potted soil at a depth of 2, 4 or 6 cm. The salinity treatments were 4.6, 8.4 and 12.2 dS m^–1. Tap water (0.8 dS m^–1) served as the control. Depth of sowing had a significant effect on seedling emergence. Seeds sown 6 cm deep showed the lowest seedling emergence. Similarly, salinity had an adverse effect on seedling emergence. The lowest seedling emergence percentages were obtained at the highest salinity treatment (12.2 dS m^–1). The interaction between salinity treatment and seeding depth was significant. Hypocotyl injury was implicated as a possible cause of poor seedling emergence in chickpea under saline water irrigation and was less severe when pre-germinated seeds were used. ILC 482 appeared to be more tolerant to salinity than Barka local, suggesting that breeding programmes involving regional exchange of germplasm may be helpful.     

Yield and Resource Use Optimization in Late Transplanted Mint (Mentha arvensis) under Subtropical Conditions

A field experiment was conducted during 1994 and 1995 at Lucknow (26.5°N, 80.5°E, 120 m above mean sea level) to optimize planting density and fertilizer-N application for high essential oil yield of late transplanted mint ( Mentha arvensis ). The treatments studied were 2.5, 2.0 and 1.66 × 10⁵ mint seedlings ha⁻¹ and 0, 80, 160 and 240 kg N ha⁻¹. Under 3 months delayed planting conditions using 2-month-old seedlings, the high planting density of 2.5 × 10⁵ plants ha⁻¹combined with 160 kg N ha⁻¹ gave significantly higher herb and essential oil yields compared with those of lower planting densities (2 and 1.66 × 10⁵ plants ha⁻¹) and all other rates of N application. It is demonstrated that a transplanted mini crop, yielding essential oil at a level of 164 kg ha⁻¹, is feasible after the harvest of rabi cereal, oil seed or legume crops in the north Indian plains.     

The Effect of Planting Date and Plant Density on Potassium and Magnesium Uptake and Harvest by Brussels Sprouts

The effects of planting date and plant density on potassium (K) and magnesium (Mg) uptake and harvest by Brussels sprouts ( Brassica oleracea var. gemmifera ) were studied in field experiments. Crop potassium concentration generally decreased towards harvest, but the pattern in potassium concentration during crop growth differed between planting dates. Plant density in the range of 2.7–4.4 plants m⁻² had no effect on crop potassium concentration. The amount of potassium in the crop at harvest decreased with a delay in planting, but was not influenced by plant density. Mainly depending on the planting date, around 100–200 kg potassium ha⁻¹, or approximately 40–50 % of the potassium in the crop at harvest, is removed from the field with the product. Averaged over treatments and years, potassium concentration in the (fresh) product was 5.2 kg ton⁻¹. The amount of magnesium in the crop at harvest decreased with a delay in planting. Depending on the planting date, uptake at harvest was 10–17 kg magnesium ha⁻¹. Plant density had no effect on this amount. On average per ton (fresh) product, 0.20 kg of magnesium was removed from the field.